Frame-mounted engine generators such as might be employed in cogeneration apparatuses or the like have conventionally been such that mounted within a frame there are: an engine, an engine-driven electric generator, an inverter (electric power converter) that converts generated electric power to a prescribed frequency, and a control panel (control box) having an internal control circuit board for a radiator fan or other such equipment.
Moreover, in the context of such a frame-mounted engine generator in which an engine, an electric generator, and so forth are mounted within a frame, a constitution in which the inverter is arranged at a rotary inner door (housing case) at the lower portion of the frame has been disclosed for improved internal equipment maintenance characteristics (see, for example, Patent Reference No. 1).